The Potential of Ankole Cattle Abattoir Ovaries for In Vitro Embryo Production

Abstract

Abstract
A study was carried out to determine the potential of abattoir ovaries from Ankole cattle cows for in vitro embryo production. Ankole cattle cows (n = 109) due for slaughter at a local abattoir were selected. The body weight, age, body condition, pregnancy status and presence of corpus luteum (CL) for each animal were recorded. Pairs of ovaries were collected from the animals and transported in PBS supplemented with 0.5 mg/ml gentamycin. The ovaries were weighed and the number of vesicular follicles (2-10 mm) on the surface recorded. Oocytes were aspirated with 18G needle and a 5 ml syringe, washed with PBS, counted and the cumulus-oocyte complexes (COCs) graded. Data were analysed using SAS, 2003 and means were separated using Fisher’s LSD at a significant level of 0.05. The mean live weight of Ankole cattle was cows 259.6 43.4 kg. Live weight increased with age and improving body condition, and live weight was higher for pregnant and cows with CL than the non-pregnant and cows without CL. The average ovary weight of Ankole cattle was 4.6 2.3 g. The left ovary weight and the ovary weight per cow increased significantly (p 0.05) between the age groups. The right ovary weight was only different (P < 0.05) between animals less than four years and those four years and above. Pregnancy and presence of CL significantly influenced (P < 0.05) the left ovary and total ovary weight, while body condition did not. The average number of vesicular follicles per pair of ovaries was 14.7 9.0 and only pregnancy influenced (P < 0.05) the number of vesicular follicles per animal. The mean oocyte yield per pair of ovaries was 8.02 ± 5.72, representing a recovery rate of approximately 54.6% for the method of follicular aspiration used. Grades I and II oocytes constituted 66% of the oocytes recovered and these were considered acceptable for in vitro embryo production. Grades II and III oocytes were different between the age-groups and pregnancy status, respectively. These results indicated a high potential for in vitro embryo production using abattoir ovaries of Ankole cattle. A further investigation of in vitro maturation, fertilization, culture and evaluation of the embryos for transfer into surrogate dams was recommended.